This invention relates to a quick disconnect liquid line coupling which is made up of mating male and female coupling elements. More particularly, this invention relates to a quick disconnect liquid line coupling whose male coupling element, when uncoupled, is capable of volumetric expansion to be able to relieve a condition of excessive pressure without venting or spillage.
The coupling elements of a quick disconnect liquid line coupling are capable of being coupled together to form a substantially leak free flow path for liquid to flow from one conduit section to another and are capable of being quickly disconnected from one another, for example, for system maintenance or replacement of a component which includes one or another of the separate conduit sections to which the coupling elements are affixed. In a coupling of such type, it is important that each of the coupling elements be closed to flow in an uncoupled condition of the coupling elements, to prevent spillage or leakage of the liquid in the line.
It is also important, in an uncoupled condition of the coupling elements of a quick disconnect coupling for a liquid line, that the coupling element for the higher pressure or upstream coupling element be capable of relieving a condition of excessive pressure, a condition which can occur, for example, due to an increase in the temperature of the liquid trapped within a relatively fixed volume. Heretofore, it has been known to provide a coupling element with a pressure relief valve to vent a portion of the trapped liquid during such a condition of excessive pressure. Unfortunately, in a coupling element of this type, the vented liquid is usually spilled or is otherwise put in an uncontained state, and this can contaminate the storage area where the system is installed, especially if the liquid in question is corrosive or otherwise environmentally objectionable.